(a) Field of the Invention
The present invention relates to a driving device and method for a plasma display panel (PDP).
(b) Description of the Related Art
A PDP is a flat panel display for displaying characters or images using the plasma generated by gas discharge, and several tens to several millions of pixels are arranged in a matrix format on the PDP depending on the PDP size. The PDP is classified as a DC PDP or an AC PDP depending on the waveforms of applied driving voltages and the configurations of discharge cells.
In general, the AC PDP driving method uses a reset period, an address period, and a sustain period sequentially.
During the reset period, wall charges formed during a previous sustain period are erased, and cells are reset so as to readily perform the next address operation. During the address period, cells that are turned on and those that are not turned on are selected, and wall charges are accumulated on the turned-on cells (i.e., addressed cells). During the sustain period, a discharge is created in the addressed cells that allows the addressed cells to take part in image display. When the sustain period begins, sustain pulses are alternately applied to the scan electrodes and sustain electrodes to sustain the discharge and display the images. As used herein, the term wall charges refers to charges that accumulate on the electrodes and are formed proximate to the electrodes on the wall (e.g., dielectric layer) of the discharge cells. The wall charges typically do not actually touch the electrodes themselves because a dielectric layer covers the electrodes. However, for simplicity in description, the charges will be described herein as being “formed on”, “stored on” and/or “accumulated on” the electrodes. Furthermore, the term wall voltage, as used herein, refers to a voltage potential that exists on the wall of discharge cells. The wall voltage is caused by the wall charges.
In a conventional PDP, a ramp waveform is applied to a scan electrode so as to establish wall charges in the reset period, as disclosed in U.S. Pat. No. 5,745,086. Specifically, a rising ramp waveform which gradually rises is applied to the scan electrode, followed by a falling ramp waveform which gradually falls. Since precise control of the wall charges greatly depends on the gradient of the ramp if ramp waveforms are applied, the wall charges are typically not controlled precisely during any given time frame.